Question

(14) The circumference of a right circular cylinder is 88 cm. Its height is 20
A cm. find the radius and curved surface area of cylinder​

Answer 1

Answer:

• Radius of cylinder = 14 cm
• Curved surface area of cylinder = 1760 cm²

Step-by-step explanation:

Given that:

• The circumference of a right circular cylinder is 88 cm.
• Its height is 20 cm.

To Find:

• The radius and curved surface area of cylinder.

Formula used:

1. C = 2πr
2. C.S.A. = 2πrh

Where,

• C = Circumference of a right circular cylinder
• C.S.A. = Curved surface area of cylinder
• r = Radius of cylinder
• h = Height of cylinder

Finding the radius of cylinder:

According to the question.

⟶ 2πr = 88

⟶ πr = 88/2

⟶ πr = 44

⟶ 22r/7 = 44

⟶ r = (44 × 7)/22

⟶ r = 14

∴ Radius of cylinder = 14 cm

Finding the curved surface area of cylinder:

⟶ C.S.A. = 2πrh

We have.

• 2πr = 88 cm
• h = 20 cm

⟶ C.S.A. = 88 × 20

⟶ C.S.A. = 1760

∴ Curved surface area of cylinder = 1760 cm²

Answer 2

Let the radius be x cm respectively.

$\underline{\bigstar\boldsymbol{According\;to\;the\;given\;Question:}}$

• Here,The circumference of a right circular cylinder is 88 cm and its height is 20 cm.we can apply the formula of circumference of cylinder to find the radius of cylinder.

As we know that,

• Circumference of cylinder = 2πr

$\\ \dashrightarrow \: \sf{88 = 2\pi r} \\ \\ \dashrightarrow \: \sf{88 = 2 \times \frac{22}{7} \times x} \\ \\ \dashrightarrow \: \sf{88 \times 7 = 2 \times 22 \times x} \\ \\ \dashrightarrow \: \sf{616 = 44 \times x}\\ \\ \dashrightarrow \: \sf{x= \frac{ \cancel{616}}{ \cancel{44}}} \\ \\ \dashrightarrow \: \underline{\boxed{\frak{x = 14}}} \red{ \bigstar}$

• Therefore,The radius of cylinder is 14 cm.

Now,Finding the curved surface area of cylinder;

As we know that,

• CSA of cylinder = 2πrh sq.units

$\\ \dashrightarrow \: \sf{CSA \: of \: cylinder = 2 \times \frac{22}{ \cancel{7}} \times \cancel{14}\times 20} \\ \\ \dashrightarrow \: \sf{CSA \: of \: cylinder =2 \times 22 \times 2 \times 20} \\ \\ \dashrightarrow \: \sf{CSA \: of \: cylinder =44 \times 40} \\ \\ \dashrightarrow \: \sf{CSA \: of \: cylinder =1760}$

• Thus,The curved surface area of cylinder is 1760 cm².

Hence,The required answer is

• The radius of cylinder is 14 cm and the curved surface area of cylinder is 1760 cm².

________________________________